clang/test/CXX/drs/dr1xx.cpp: Add explicit triple x86_64-unknown-unknown to satisfy check7a and check8a since r194240.

For i686 targets and LLP64 targets, we can see;
  error: 'error' diagnostics seen but not expected:
    File clang/test/CXX/drs/dr1xx.cpp Line 761: 'check7a' declared as an array with a negative size
    File clang/test/CXX/drs/dr1xx.cpp Line 765: 'check8a' declared as an array with a negative size
  2 errors generated.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@194246 91177308-0d34-0410-b5e6-96231b3b80d8

test/CXX/drs/dr1xx.cpp

@@ -1,6 +1,6 @@
-// RUN: %clang_cc1 -std=c++98 %s -verify -fexceptions -fcxx-exceptions -pedantic-errors
-// RUN: %clang_cc1 -std=c++11 %s -verify -fexceptions -fcxx-exceptions -pedantic-errors
-// RUN: %clang_cc1 -std=c++1y %s -verify -fexceptions -fcxx-exceptions -pedantic-errors
+// RUN: %clang_cc1 -std=c++98 -triple x86_64-unknown-unknown %s -verify -fexceptions -fcxx-exceptions -pedantic-errors
+// RUN: %clang_cc1 -std=c++11 -triple x86_64-unknown-unknown %s -verify -fexceptions -fcxx-exceptions -pedantic-errors
+// RUN: %clang_cc1 -std=c++1y -triple x86_64-unknown-unknown %s -verify -fexceptions -fcxx-exceptions -pedantic-errors
 
 namespace dr100 { // dr100: yes
   template<const char *> struct A {}; // expected-note {{declared here}}